The equipment for heating a wafer during a semicon-ductor

Chapter 12, Problem 12.97

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The equipment for heating a wafer during a semicon-ductor manufacturing process is shown schematically.The wafer is heated by an ion beam source (not shown)to a uniform, steady-state temperature. The large chambercontains the process gas, and its walls are at a uniformtemperature of Tch?400 K. A 5 mm?5 mm target areaon the wafer is viewed by a radiometer, whose objec-tive lens has a diameter of 25 mm and is located500 mm from the wafer. The line-of-sight of theradiometer is off the wafer normal.(a) In a preproduction test of the equipment, a blackpanel (??1.0) is mounted in place of the wafer.Calculate the radiant power (W) received by theradiometer if the temperature of the panel is 800 K.(b) The wafer, which is opaque, diffuse-gray with anemissivity of 0.7, is now placed in the equipment,and the ion beam is adjusted so that the powerreceived by the radiometer is the same as thatfound for part (a). Calculate the temperature of thewafer for this heating condition.